A variety of hosiery articles are formed on circular knitting machinery, coming off the machinery in the form of generally tubular articles. The toe portions of the articles typically are not closed on the circular knitting machine. Instead, the articles are taken off the knitting machine with open toe ends that are subsequently closed by sewing in a sewing machine. In many cases, a shaped heel portion may be knit into the article. Particularly in the case of hosiery with a shaped heel, it is desirable for the seam closing the toe end to be made in a predetermined orientation relative to the heel.
In the case of socks, often the socks are knit to have a shaped toe portion that curves upward from the sole portion toward the instep portion of the sock, and the seam across the toe end desirably is positioned such that it is above, or at least is not below, the toes of the wearer. The term “socks” hereinafter will be used to refer to hosiery articles that do not extend above the knee of the wearer when in the fully extended position of normal use, and which are knit from relatively coarse yarns. Included in the category of “socks” are crew socks, mid-calf socks, knee-high socks, sports socks, and the like. Such socks are typically knit with less than about 700 stitches per square inch. In socks having shaped toe portions and/or shaped heel portions, it is desirable for the seam closing the toe end to extend generally across the toes. To achieve this result, it is necessary for the open-toe sock blanks to be fed into the toe-closing sewing machine in a particular orientation.
The process of feeding open-toe sock blanks into toe-closing sewing machines has been performed manually in many manufacturing plants. In other cases, an automated device for feeding the blanks into the sewing machine has been used, but in all of the known devices in widespread commercial use it has still been necessary for a human attendant to orient the blanks properly on the feeding device. The need for manual intervention by human attendants is obviously undesirable from the standpoint of productivity and efficiency of the manufacturing operation.
In the manufacture of women's nylon hose and the like, efforts have been made to automate the entire process of properly orienting the open-toe hose blanks and feeding the oriented blanks into the sewing machine. For example, Detexomat Machinery Limited of the United Kingdom has developed machines that orient nylon hose blanks and feed them into a seamer. An example of such a machine is described in U.S. Pat. No. 4,383,491. The machine is a rotary device having ten tubular carriers on which hose blanks are sleeved. The tubular carriers are mounted on a rotary turret, which rotates to transport each carrier to each of ten stations arranged about the periphery of the turret. Each carrier includes a pair of reciprocally movable finger blades that extend radially outward from diametrically opposite sides of the tubular carrier. At a first station, an operator loads a hose blank onto the carrier disposed at the first station so that the hose blank is sleeved over the tubular carrier and the finger blades. The turret then rotates to transport the hose blank to the second station having a wind-on roller that engages the hose blank and is driven to draw the blank fully onto the carrier, the roller being disengaged from the blank when a photo-sensor detects the toe end of the blank on the carrier. The hose blank is then advanced to the third station having a positioner that longitudinally positions the toe end of the blank on the carrier with the aid of a photo-sensor that detects when a discernable feature of the toe end becomes longitudinally aligned with the photo-sensor. The blank is then advanced to the fourth station, where the blank is positioned rotationally so that the toe end is in a predetermined orientation relative to a clamp means that will later clamp the toe end for seaming the toe end. The rotational position of the blank is controlled by a positioning means that frictionally engages the blank on the tubular carrier and rotates the blank about the carrier and the finger blades. Various positioning means that are moved into and out of engagement with one side of the hose blank are disclosed, including a padded roller driven about an axis parallel to the axis of the tubular carrier, a driven belt looped about a pair of rollers, and a bar that is driven tangentially relative to the tubular carrier. The positioning means is disengaged from the blank when a photo-sensor detects an indicating mark on the hose blank. The patent states that the indicating mark can be knitted into the hose using a contrasting thread. The machine includes a seamer at another station for closing the toe ends of the hose blanks.
The machine described in the '491 patent is a relatively complicated and expensive piece of equipment, and yet still requires a human attendant to load hose blanks onto the carriers. The machine is intended to be a replacement for a separate sewing machine, but likely would cost considerably more than a simple sewing machine that is dedicated to closing toe ends of hosiery articles. Moreover, the finger blades used for spreading the hose blanks for seaming may allow a relative smooth-knit fabric such as nylon hose to freely rotate about them when orienting the blanks, but with a coarser-knit fabric such as typically used in socks it is anticipated that the finger blades may not allow free rotation of the sock blanks. The roller, belt, or bar used for rotating the hose blanks about the tubular carriers and finger blades engages only a small fraction of the circumference of the blanks; accordingly, if there is any resistance of the blank to rotation about the carrier and finger blades, it is expected that the blank would stretch and deform, thereby compromising the accuracy with which the blank can be rotationally positioned for seaming.
What is needed is an automated apparatus and method for orienting the open toe ends of socks for sewing in a sewing machine. Preferably, the apparatus and method should be readily adaptable for use with existing sewing machines.
The assignee of the present application has developed such an apparatus and method, which are described in U.S. Pat. No. 6,158,367, the entire disclosure of which is incorporated herein by reference. The apparatus of the '367 patent represented a vast improvement over the conventional process of manually orienting and feeding socks to a sewing machine. Further improvements in the apparatus and method continue to be sought, however, and the present invention has resulted from such efforts.